When providing counseling on make-up, in order to select colors of lipstick and other cosmetics that match that person's skin color, it is necessary to have an accurate understanding of skin color.
In Japanese Laid-Open Patent Application No. 10-174733, the present applicant has proposed a system for providing make-up counseling by measuring and classifying the color of the skin of a person's face and acquiring a facial image. In this system, a strobe and digital camera, as well as a halogen lamp for spectral measurements, are provided inside a measurement unit. The measurement unit is then positioned at a predetermined distance from a chair in which the subject sits. A half mirror is provided at the front of the measurement unit, and the subject's posture is then adjusted so that the center of the face aligns with a reference line inscribed on the half mirror and indicating the photographic center. The skin color is measured by analyzing the reflected light with a spectrometer at the same time as other processes are carried out as well.
The conventional measurement unit is an elaborate affair, having a half mirror on the front and containing a strobe and camera as well as a halogen lamp and a spectrometer. The large scale and the cost of such apparatuses were drawbacks.
In reducing the scale of the system, it might appear that the halogen lamp and the spectrometer can be eliminated and skin color measurement obtained easily from the facial image as photographed by the digital camera. However, the luminance and the color of the facial image changes due to the effects of external light from the environment in which the system is located, and moreover, fluctuations in the distance from the digital camera to the subject causes the luminance of the facial image to change, resulting in the problem that the skin color cannot be measured accurately, that is, without being affected by the environment.